The field of the present invention is the testing of brittle materials in tension, and more particularly, the application of uniaxial tensile loads to brittle materials to determine tensile strength
Tensile testing of brittle materials such as cement and concrete has been an unsolved problem for some time, as evidenced by the fact that in 1968, ASTM Specifications for tensile testing of cement mortar specimens (ASTM C190) were discontinued due to lack of reproducible test results.
Difficulties associated with the testing of brittle materials in tension stem from several sources. The apparatus for gripping the typically cylindrical test specimen may cause a fracture in the "grip" due to stress risers such as teeth, etc. Localized failure may also result from lack of axial alignment of the specimen. If either of these conditions are present, the specimen can fail prematurely and accurate results will not be obtained. A second area of concern is elastic rebound caused by the release of energy when a matrix material such as concrete fractures in tension. Rebound will introduce a shock load in the remaining material causing it to break at a load lower than its real tensile value.
Accordingly, a device and method for the tensile testing of brittle material that overcomes these problems would be desirable.